IQmath Library

IQNrmpy
IQ Multiplication with rounding (IQN*IQN)
Description
Declaration
This function multiplies two IQ number and rounds the result. In cases
where absolute accuracy is necessary, this operation performs the IQ
multiply and rounds the result before storing back as an IQ number. This
gives an additional 1/2 LSBit of accuracy.
Global IQ function (IQ format = GLOBAL_Q)
_iq _IQrmpy(_iq A, _iq B)
Q format specific IQ function (IQ format = IQ1 to IQ30)
_iqN _IQNrmpy(_iqN A, _iqN B)
Input Format
Global IQ function (IQ format = GLOBAL_Q)
Input “A” & “B” are IQ number in GLOBAL_Q format
Q format specific IQ function (IQ format = IQ1 to IQ30)
Input “A” & “B” are IQ number in IQN format
Output Format
Global IQ function (IQ format = GLOBAL_Q)
Result of multiplication in GLOBAL_Q format
Q format specific IQ function (IQ format = IQ1 to IQ30)
Result of multiplication in IQN format.
Usage
Example 1:
Following code computes "Y = M*X + B" in GLOBAL_Q format with
rounding but no saturation:
_iq Y, M, X, B;
Y = _IQrmpy(M,X) + B;
Example 2:
Following code computes "Y = M*X + B" in IQ10 format with rounding but
no saturation:
_iq10 Y, M, X, B;
Y = _IQ10rmpy(M,X) + B;
©Texas Instruments Inc., June 2002 24